EAST TENNESSEE GEOLOGICAL SOCIETY
September 2007 Meeting


Monday, September 10, 2007
6:00 - 7:30 pm

Pellissippi State Technical Community College
10915 Hardin Valley Road, Knoxville
Lamar Alexander Building, Room 223

SEPTEMBER PRESENTATION

Evaluation of Fluorescent Dissolved Organic Material
in Karst Aquifers of East Tennessee

Terri Brown
Graduate Student
University of Tennessee
Dept of Earth & Planetary Sciences
Knoxville, Tennessee

Larry McKay (1), Joe Zhuang (2), John McCarthy (1), Randy Gentry (2), Sid Jones (3)

(1) Dept. of Earth & Planetary Sciences, Univ. of Tennessee, Knoxville TN
(2) Institute for a Secure and Sustainable Environment, Univ. of Tennessee, Knoxville, TN
(3) Tennessee Department of Environment and Conservation, Oak Ridge, TN

Abstract

This study investigates the occurrence of background fluorescence in public groundwater supplies in East Tennessee. One of our principal goals is to assess the influence of background fluorescence on the ability to conduct dye tracer experiments with very low concentration dye injections. Low concentration dye tracing is desirable because it would allow the use of dyes to delineate Source Water Protection Areas (SWPA) with minimal risk of producing colored water in public supply wells and springs. A second goal is to determine whether the &ldquofingerprint&rdquo of fluorescent dissolved organic matter (FDOM) can be used to identify sources of recharge. In general, FDOM exhibit wavelength and fluorescence intensity variations related to climate, soils and vegetative cover, and show potential as natural tracers of land use activity and nonpoint source impacts. Raw water samples are being collected on a quarterly basis from a number of community groundwater sources across East Tennessee. Fluorescent properties are measured with a Perkin-Elmer Model LS 55 Luminescence Spectrometer and interpreted using excitation-emission ratios and trend analysis. Preliminary data provide a snapshot of spatial and temporal FDOM fluctuations in karst aquifers of the Valley and Ridge.


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